holo.py does globing in holo initial class

[emlynjdavies]

globing should be replaced by the FileHander to avoid bugs in reading txt file lists. But maybe all of holo initial can be moved into the load class (similar to how backgrounding is handled)? @nepstad can describe this.

[nepstad]

I suggest storing the holo kernel and image stack on the pipeline data object (which will carry it through the processing). Check if these exist in the pipeline inside the holo step, and if not call the constructor.

[animmosmith]

Good suggestion, thanks. Implemented this in #391: Initial now just stores the reconstruction parameters on the pipeline data, and Reconstruct builds kern/im_stack lazily on its first call using the dimensions of the actually-loaded image. No globbing/file listing needed for holo setup at all now. Config interface for Initial is unchanged so existing config.toml files keep working.